The University of California, San Francisco/San Francisco General Hospital Latino Mental Health Research Program is launching research efforts to reduce the number of new cases of major depression in high-risk, low-income, Spanish-and English-speaking pregnant women. The program, called Mamas y Bebes (Mothers and Babies/Mood and Health Project) is intended to benefit the mother-to-be and the infant by sparing them the pain and dysfunction associated with major depression, and reducing the sequelae of being raised by a clinically depressed mother. The long-term goal is to carry out a randomized controlled trial to test this preventive intervention. This proposal is to develop the trial protocol in Spanish and English for use with young (18-to 25-year old) pregnant women. The Depression Prevention Course, a group cognitive-behavioral intervention, will be adapted to address the experiences most salient during pregnancy, birth, and the first year of motherhood. The Course teaches participants methods to regulate their emotions to prevent full-blown major depressive episodes (MDE). Obstetrics patients will be screened for MDE. Those who meet criteria for MDE or other major psychiatric disorders will be referred for treatment and screened out of the study. Those who do not meet criteria for major psychiatric disorders but are at high risk for MDE will be offered entry into this part of the study. The study will evaluate recruitment and retention methods into the study, training technology, protocol adherence and instructor proficiency measures, and carry out three cycles of implementation and revision of the protocols. Effect sizes on changes in depressive symptoms and their cognitive and behavioral mediators will be obtained for power calculations for the randomized trials.